make ZoomContainer work with real-time data

demo/components/debug-demo.js

@@ -1,52 +1,47 @@
 /*eslint-disable no-magic-numbers */
+/*global setInterval:false */
+
 import React from "react";
 import {
-  VictoryChart, VictoryLine, VictoryGroup, VictoryBrushContainer
+  VictoryChart, VictoryLine, VictoryZoomContainer
 } from "../../src/index";
 
-const data = [
-  { x: 1, y: -3 },
-  { x: 2, y: 5 },
-  { x: 3, y: 3 },
-  { x: 4, y: 0 },
-  { x: 5, y: -2 },
-  { x: 6, y: -2 },
-  { x: 7, y: 5 }
-];
+import { range, last } from "lodash";
+
+const y = (x) => Math.sin(x / 10);
+const initData = () => range(70).map((x) => ({ x, y: y(x) }));
 
 class App extends React.Component {
   constructor() {
     super();
-    this.state = {};
-  }
-  handleSelectionChange(domain) {
-    this.setState({
-      selectedDomain: domain
-    });
-  }
-  changeSelection(a, b) {
-    this.setState({
-      selectedDomain: { x: [a, b] }
-    });
+    this.state = {
+      data: initData(),
+      zoomDomain: null
+    };
+
+    setInterval(() => {
+      const { data } = this.state;
+      const x = last(data).x + 1;
+
+      if (x > 1000) {
+        this.setState({ data: initData() });
+      } else {
+        data.push({ x, y: y(x) });
+        this.setState({ data });
+      }
+    }, 20);
   }
   render() {
     return (
-      <div style={{ width: 300 }}>
-        <button onClick={() => this.changeSelection(1, 3)}>1-3</button>
-        <button onClick={() => this.changeSelection(3, 6)}>3-6</button>
-        <VictoryChart
-          containerComponent={
-            <VictoryBrushContainer
-              dimension="x"
-              onDomainChange={this.handleSelectionChange.bind(this)}
-              selectedDomain={this.state.selectedDomain}
-            />
-          }
-        >
-          <VictoryGroup data={data}>
-            <VictoryLine/>
-          </VictoryGroup>
-       </VictoryChart>
+      <div style={{ maxWidth: 500 }}>
+        <VictoryChart containerComponent={<VictoryZoomContainer dimension="x" />}>
+          <VictoryLine
+            data={this.state.data}
+          />
+          <VictoryLine
+            data={this.state.data}
+          />
+        </VictoryChart>
       </div>
     );
   }

src/components/containers/victory-zoom-container.js

@@ -26,7 +26,8 @@ export const zoomContainerMixin = (base) => class VictoryZoomContainer extends b
   static defaultProps = {
     ...VictoryContainer.defaultProps,
     clipContainerComponent: <VictoryClipContainer/>,
-    allowZoom: true
+    allowZoom: true,
+    zoomActive: false
   };
 
   static defaultEvents = [{
@@ -131,12 +132,23 @@ export const zoomContainerMixin = (base) => class VictoryZoomContainer extends b
     const childComponents = React.Children.toArray(props.children);
 
     return childComponents.map((child) => {
-      const { currentDomain } = props;
+      const { currentDomain, zoomActive } = props;
       const originalDomain = defaults({}, props.originalDomain, props.domain);
       const zoomDomain = defaults({}, props.zoomDomain, props.domain);
       const cachedZoomDomain = defaults({}, props.cachedZoomDomain, props.domain);
-      const domain = isEqual(zoomDomain, cachedZoomDomain) ?
-        defaults({}, currentDomain, originalDomain) : zoomDomain;
+
+      let domain;
+      if (!isEqual(zoomDomain, cachedZoomDomain)) {
+        // if zoomDomain has been changed, use it
+        domain = zoomDomain;
+      } else if (!zoomActive) {
+        // if user has zoomed all the way out, use the child domain
+        domain = child.props.domain;
+      } else {
+        // default: use currentDomain, set by the event handlers
+        domain = defaults({}, currentDomain, originalDomain);
+      }
+
       let newDomain = props.polar ? this.modifyPolarDomain(domain, originalDomain) : domain;
       if (props.dimension) {
         // if zooming is restricted to a dimension, don't squash changes to zoomDomain in other dim

src/components/containers/zoom-helpers.js

@@ -61,8 +61,12 @@ const Helpers = {
     ];
   },
 
+  zoommingOut(evt) {
+    return evt.deltaY > 0;
+  },
+
   getScaleFactor(evt) {
-    const sign = evt.deltaY > 0 ? 1 : -1;
+    const sign = this.zoommingOut(evt) ? 1 : -1;
    // eslint-disable-next-line no-magic-numbers
     const delta = Math.min(Math.abs(evt.deltaY / 300), 0.5); // TODO: Check scale factor
     return Math.abs(1 + sign * delta);
@@ -232,16 +236,22 @@ const Helpers = {
       y: dimension === "x" ? lastDomain.y : this.scale(y, evt, targetProps, "y")
     };
     const resumeAnimation = this.handleAnimation(ctx);
+
+    const zoomActive = !this.zoommingOut(evt) // if zoomming in or
+      // if zoomActive is already set AND user hasn't zoommed out all the way
+      || (targetProps.zoomActive && !isEqual(originalDomain, lastDomain));
+
     if (isFunction(onDomainChange)) {
       onDomainChange(currentDomain);
     }
+
     return [{
       target: "parent",
       callback: resumeAnimation,
       mutation: () => {
         return {
           domain: currentDomain, currentDomain, originalDomain, cachedZoomDomain: zoomDomain,
-          parentControlledProps: ["domain"], panning: false
+          parentControlledProps: ["domain"], panning: false, zoomActive
         };
       }
     }];